<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      div {
        width: 100px;
      }
    </style>
  </head>
  <body>
    <div id="box" style="width: 400px; font-size: 2rem">hello div</div>
    <script>
      const box = document.getElementById("box");

      // -moz-border-radius
      // MozBorderRadius

      setTimeout(() => {
        console.log(box.style.width);
        console.log(box.style.fontSize);
        console.log(box.style.fontStyle);
        box.style.backgroundColor = "yellow";
        box.style.border = "1px solid red";
      }, 3000);

      setTimeout(() => {
        // box.style.width = "none";
        box.style.width = "";
      }, 5000);
    </script>
  </body>
</html>
